There are so many methods tips to do this but here are few tips based on my own experience.
1) Unique products you need a unique design I don't mean to reinvent the wheel but something which makes your products designs unique. 2) Upload your designs on multiple products don't just limited to few products like tshirt mugs etc. 3) Do not copy other designers work, take an inspiration and idea from them but then work on your own creative skills to make your designs.
4) you don't need to be a pro seller or have good sales history for getting your products as selected by editor it's not important for you.
5) Do your research and find niche you wnat to target for getting selected in editor pick.
6) Upload more it's obvious but people ignore it as more your Upload more it increases your chances to being selected by editor.
7) easily editable template easily accessible by your customer.
8) the relevant title description for your designs.
9)ofixing 2 niches or the ore can be a great idea to bridge the gap and also to make unique
designs and products.
10 ) please be patient it will take sometime it doesn't happen overnight If you want to know more in depth then watch my youtube video here .